DK172850B1 - Process for making an article with friction-reducing surface coating as well as coating material for use - Google Patents

Abstract

A method of producing an article with a coating having friction-reducing properties in wet condition, said coating comprising a binder (a), a hydrophilic polymer (b), as well as, if desired, an osmolality-increasing compound (c), whereby a dispersion is produced from (a) a binder in form of a hardenable prepolymer of a molecular weight of at least 200, (b) one or more hydrophilic polymers, (c) if desired, an osmolality-increasing compound, and (d) a solvent or a mixture of solvents, in which (a) is substantially insoluble, applying said dispersion onto the article, removing the solvent or a portion thereof, and hardening the binder, as well as a coating material for this purpose. A durable coating is obtained having good slide properties even after a long stay in an aqueous environment, such as within a body cavity.

Description

in DK 172850 B1

The present invention relates to a process for preparing an article having a wettable friction-reducing coating comprising a binder (a), a hydrophilic polymer (b) and, if desired, an osmolality enhancing compound (c), and a coating material for use in the process.

In particular, but not exclusively, the invention can be used in the manufacture of articles of the kind intended for surgical, medical or diagnostic use, e.g. articles for insertion into a body cavity such as catheters, guide wires, wound wires and fiber optic articles, which articles may be made of plastic, e.g. PVC or polyurethane, or of metal or glass.

Several examples of such objects are known, e.g. catheter, with a friction-reducing coating. The presence of the friction-reducing coating causes, in connection with catheters, that the surface of the catheter becomes greasy and lubricated as the catheter is dipped into an aqueous, optionally saline solution or introduced into the body cavity prior to insertion into a body cavity. 15 containing body fluid. This results in a significant reduction in the genes that the catheter introduces and removes in the body cavity. In addition, a significant reduction in the risk of damage to sensitive tissue is achieved with the use of the catheter.

The desired lubricating effect can be achieved by the slow release of hydrophilic polymer.

In the case of orphan substances to be introduced As the human body and, as a matter of course, should be able to be extracted after a prolonged period of residence in the body, it is essential that a sufficient amount of hydrophilic polymer be released at all times when the lubricating effect is desired, i.e. both during insertion and later extraction.

The problem of producing hydrophilic coatings which, in order to have a sufficient hydrophilicity, must contain a substantial proportion of hydrophilic polymer, is that DK 172850 B1 2 hydrophilic polymers are difficult to retain on the surface of solid articles, especially when they are made of hydrophobic materials such as PVC or polyurethane. Therefore, it is usually necessary to use a binder in the form of a hydrophobic material, which binder, however, reduces the hydrophilic nature of the surface and its ability to become smooth and lubricating in the wet state.

An overview of the prior art regarding hydrophilic lubricants, i. Friction-reducing medical coatings are given in an article by Y.L. From "HYDROPHILIC LUBRICIOUS COATINGS FOR MEDICAL APPLICATIONS" from "POLYMERIC MATERIALS SCIENCE and ENGINEERING"; Proceedings of the 10 ACS Division of Polymeric Materials: Science and Engineering, Volume 63, Autumn Meeting 1990, Washington, D.C. published in 1990 by AMERICAN CHEMICAL SOCIETY.

In U.S. Patent No. 5,005,287, which corresponds to European Patent Specification No. 289,996, Ritter proposes a method of applying a smooth, moisturizing surface coating to a razor unit on the sides which, during wet shaving, slides against the skin. As a coating, a solution containing a water-soluble polymer, in particular poly-N-vinylpyrrolidone (PVP), is used together with a radical-polymerizable vinyl monomer and a photoinitiator which, by irradiation, decomposes into free radicals.

As a vinyl monomer, Ritter according to the examples uses tetrahydrofuranyl-2-methylacrylate or a combination of N-vinylpyrrolidone and trimethylolpropane monoacrylate, all of which are relatively low molecular weight compounds. Such low molecular weight monomers are usually undesirable in connection with materials which must be in contact with the human body for a prolonged period of time, as such compounds are often harmful to health. When coating plastic materials, such as PVC or polyurethane, such monomers can readily penetrate the plastic material so that they will not be active participants in the curing polymerization process undertaken after the coating process. This means that in practice it is extremely difficult or impossible to avoid residues of unreacted monomers in the finished articles.

DK 172850 B1 3

As mentioned, Ritter employs a coating solution which must contain the hydrophilic polymer (s) which ensures the desired friction-reducing properties of the coating.

However, it is also desirable that the coating be sufficiently retained on the coated article even after prolonged residence in an aqueous environment such as body cavity. Thus, it will usually be desirable to use a binder with a sufficient affinity for the article to be coated. In the case of a coating on an object which has to be introduced into the human body for a long time, it is particularly important that this affinity is sufficiently large. To ensure this, it will usually be necessary that the binder itself has a relatively strong hydro · 10 fob character. The task can therefore be difficult to solve if, as suggested by Ritter, a coating material is used, in which all the constituents are in dissolved form, since a binder with a sufficiently good affinity for the article to be coated will be difficult to dissolve in a solvent which also suitable for dissolving the hydrophilic polymers, especially if one wishes to avoid the use of a monomeric starting material 15 for the binder. In addition, if it is really possible to apply both a hydrophilic polymer and a sufficiently effective binder in the same solvent, it will be difficult to control the obtained structure of the binder and the hydrophilic polymer in the finished coating.

In the manufacture of durable friction-reducing coatings, it is a difficult compromise solution to provide both the desired hydrophilicity combined with a bond which ensures that the hydrophilic polymer is only slowly washed out and at the same time ensures that the coating is sufficiently attached to the coated object. The factors that particularly influence the result are as follows: The weight ratio of the hydrophilic polymer (b) to the hydrophobic binder (a).

25 - Molecular size of the hydrophilic polymer (b). It should be noted here that even with a relatively large molecular size of the hydrophilic polymer (b), there is still a risk of too rapid leaching of the hydrophilic polymer.

DK 172850 B1 4

The degree of hydrophilicity / hydrophobicity of the binder (a). If the binder has only a limited degree of hydrophobicity corresponding to some hydrophilicity, an excellent affinity between the binder (a) and the hydrophilic polymer (b) is obtained, but this is at the expense of the affinity between the article to be coated and the binder 5 ( a).

In light of this problem, various solutions have been proposed. In U.S. Patent Nos. 4,487,808 and 4,666,437, it is proposed to apply two coatings sequentially so that first a solution of a compound having at least two unreacted isocyanate groups is applied first. molecule followed by evaporation of the solvent, after which a solution of a hydrophilic polymer, respectively polyethylene oxide or PVP, is applied again followed by evaporation of the solvent and the material is cured at an elevated temperature. In this coating form, by means of the unreacted isocyanate groups, a certain bonding of the hydrophilic polymer is achieved. Thereby, some of the groups which give the hydrophilic polymer its hydrophilic properties are bonded, such that there is some reduction in the hydrophilic properties of the coating. On the other hand, if this binding of the hydrophilic groups is restricted, it will not be possible to safeguard against the rapid leaching of the hydrophilic polymer.

It would be advantageous to ensure an appropriate structure in the coating, wherein the binder (a) and the hydrophilic polymer (b) are distributed in such a way that both a good attachment to the coated article and a sufficient retention of the hydrophilic polymer (b) against unwanted rapid leaching.

DK patent specification 165415 discloses a method in which this problem is solved by applying a coating material comprising a mixture of a hydrophobic polymer as a binder in the form of polyurethane without free isocyanate groups, ie. substantially finished reacted polyurethane, and a hydrophilic polymer in the form of PVP in at least two solvents of different volatility, the two solvents being a solvent system adapted in such a way that the polyurethane is at least both are soluble in the mixture of solvents and in the heaviest volatile of the two solvents, while PVP is soluble in the most volatile of the solvents and at most partially soluble in the heaviest volatile of the solvents. By using this method, a controlled precipitation of the two polymers is obtained, with the first 5 precipitation of PVP, namely when the most volatile of the solvents is evaporated. This results in an improved distribution of the two polymer components. With the method, a ratio of the hydrophilic polymer (PVP) to the binder can be used in a weight ratio of 1.5: 1- 5: 1, preferably 2: 1-3: 1. To improve the hydrophilic nature of the overall coating, it would be desirable if the proportion of the hydrophilic polymer could be increased.

US Patent No. 5,041,100 (Rowland et al.) Discloses a friction reducing coating which e.g. may be applied to the outside surface of a catheter. The coating material comprises an intimate mixture of polyurethane and high molecular weight polyethylene oxide.

This coating material, which does not require subsequent curing, comprises a dispersion of both the polyurethane which acts as a binder and the polyethylene oxide which acts as a hydrophilic reducing reducing polymer. In the practical examples, Rowland obtains only a modest proportion of the hydrophilic polymer of not more than 0.125 parts by weight of polyethylene oxide per liter. part by weight of polyurethane binder which will only provide a modest friction reducing effect.

It has now been found that a hydrophilic coating having reduced friction in the wet state can be provided with a high proportion of hydrophilic polymer while obtaining a good adhesion of the coating when, instead of applying hydrophilic polymer and binder, either as two separate coating solutions or in the form of a common solution or dispersion thereof, apply a coating material in the form of a dispersion, which is known, as is known, of a dispersion phase dispersed in a dispersant containing the binder. the dispersed phase, while the hydrophilic polymer or a portion thereof is dissolved in the dispersant and wherein the binder is curable.

DK 172850 B1 6

Thus, the process of making an article having a wettable anti-friction coating comprising a binder (a), a hydrophilic polymer (b) and, if desired, an osmolality-increasing compound (c), is characterized in that from 5 ( a) a binder in the form of a radiation curable urethane acrylate prepolymer having a molecular weight of at least 200, (b) one or more hydrophilic polymers selected from polyvinylpyrrolidone, polyethylene glycol, CMC and alginate, (c) if desired, an osmolality enhancing compound, and 10 (d) a solvent or a mixture of solvents wherein (a) is substantially insoluble using 0.5-60 parts by weight of hydrophilic polymer (b) per ml. part by weight of binder (a), produces a dispersion, applies the dispersion to the article, removes the solvent or part thereof, and cures the binder.

By using the method of the invention, significant advantages are obtained over the technique known from US Patent No. 5,005,287 (Ritter) and DK Patent No. 165415, respectively, in contrast to not using a solvent , wherein the vinyl monomer or binder component, respectively, is soluble but, on the contrary, applies the coating in the form of a dispersion. Hereby a solvent may be used as a dispersant in which only the hydrophilic polymer and any osmolality enhancing compound, e.g. sodium chloride, can be dissolved, i. water can usually be used as a dispersant and solvent. Thus, the use of organic solvents such as e.g. methylene chloride which may tend to penetrate e.g. a PVC article and, moreover, may be difficult to remove from the coating material dry matter, and thus may be present as residues in the manufactured article. Namely, solvents with high affinity for the binder and the article itself will be rapidly absorbed therein, thereby becoming difficult to remove from the article produced even after sterilization.

Such organic solvents are known to be detrimental to the human organism and are generally undesirable.

S Using a dispersion as a coating material, where the binder is not to be present in dissolved form, provides the additional advantage of using more difficult soluble prepolymers as a binder, thereby avoiding the use of monomers which may have adverse health effects.

By using a binder that cures after the coating process, the placement of the binder in the coating can be tailored to this particular task. The binder is applied as the dispersed phase in undissolved form and thus elites harden a structure resulting from the structure of the dispersed phase. It is believed that after the application, the disperse phase will form a network from the initially substantially spherical particles, e.g. droplets which, after confluence or packing, are adhered to each other and to the article being coated, in such a way as to obtain a structure which can excellently both retain the hydrophilic polymer and control the desired leaching thereof in the practical application situation to achieve a long-lasting lubricating effect.

It has been found that the process according to the invention provides a durable and excellent adhesive coating on a flexible article where the ratio of hydrophilic polymer to hydrophobic binder is up to approx. 29: 1, cf. Example 1, ie. substantially higher than that obtainable in Danish Patent Specification No. 165415. The practical upper limit of the proportion of hydrophilic polymer is usually given in the increased tendency for the coating to become brittle or brittle. This tendency is particularly pronounced where the coated article is of flexible material. Thus, it has been found possible to apply to a non-flexible material a similarly durable coating in which the ratio of hydrophilic polymer to hydrophobic binder is even higher, e.g. 55: 1st

DK 172850 B1 8

A high proportion of hydrophilic polymer in the coating material is of course an advantage in ensuring the desired lubricating effect in the wetted state. In addition, an additional advantage is that one can keep the amount of radiation curable binder at a very low level. This makes it possible to use a radical-polymerizable binder of the kind that requires radiation curing for the presence of a photoinitiator. The low amount of the binder means that you can only use a correspondingly low amount of photoinitiator, which is considered to be harmful to health and can irritate the mucous membranes. In addition, photoinitiators can cause odors.

The invention also relates to a coating material comprising a binder (a), a hydrophilic polymer (b) and, if desired, an osmolality-increasing compound (c), which coating material is characterized in that it is designed as a dispersion comprising a dispersion phase dispersed in a dispersion agent phase, which is made from (a) a binder in the form of a radiation curable urethane acrylate prepolymer having a molecular weight of at least 200, (b) one or more hydrophilic polymers selected from polyvinylpyrrolidone, polyethylene glycol, CMC and alginate, (c) if desired, an osmolality enhancing compound, and (d) a solvent or a mixture of solvents wherein (a) is substantially insoluble, which coating material contains 0.5-60 parts by weight of hydrophilic polymer (b) per liter. 1 part by weight of binder (a).

According to an advantageous embodiment of the coating material, the hydrophilic polymer component (b) may be composed of (b) one or more hydrophilic polymers which are only soluble in the dispersant phase, and one or more hydrophilic polymers, which are essentially completely soluble in the dispersant phase.

According to a further advantageous embodiment, the coating material of the invention may comprise 5 3.5 - 15 parts by weight of radiation curable urethane acrylate prepolymer (a), 60 - 240 parts by weight of the first hydrophilic polymer (b1), 50 - 200 parts by weight of the second hydrophilic polymer (b2), 22 - 90 parts by weight of osmolality increasing compound (c), and 140-560 parts by weight of solvent (d).

As an example of a hydrophilic polymer of type (b1) may be mentioned polyethylene glycol (PEG) and as an example of the hydrophilic polymer (b2) may be mentioned poly vinylpyrrolidone (PVP), which hydrophilic polymers can advantageously be used with water as the solvent ( d).

An advantageous radiation curable binder (a) is one or more radically polymerizable binder. If the coating material contains a UV curable or a laser beam curable binder, the coating material will usually further comprise a photoinitiator which may preferably be an inherently free photoinitiator capable of forming free radicals, which photoinitiator may advantageously have such a structure that each of the free radicals formed contains an ethylenic unsaturation. This ensures that the photoinitiator copolymerizes with the binder so as to avoid residues of unreacted free radicals.

The invention will be explained in more detail below.

As mentioned, in the method of the invention, a coating material is used in the form of a dispersion, usually an emulsion.

DK 172850 B1 10

This dispersion can be prepared using a solvent, e.g. water in which the binder used is insoluble.

By using a dispersion in which the binder is insoluble and thus will be in the form of small spherical particles forming the dispersive phase, it has been found that an advantageous structure can be obtained in the finished coating. After application, the spherical particles present in the coating material will collapse as the solvent is evaporated, after which the binder can be cured to obtain an advantageous cohesive mesh structure.

Such a structure cannot be obtained if a dissolved binder (a) is used, since using dissolved materials does not have the same ability to control the final structure conditioned by such factors as the conditions of solvent evaporation and solubility conditions. for the materials in the coating.

Thus, it is an important prerequisite of the process of the invention that an unresolved radiation-curable binder (a) is used.

Thus, for the sake of the structure of the finished coating, as the binder (a), any radiation curable urethane acrylate prepolymer binder which is insoluble in the solvent used can be used.

When the article of the invention according to the invention with friction-reducing surface bell is an article intended for insertion into a body cavity, e.g. Of course, for surgical, medical or diagnostic use, special requirements are made for the coating material used, which must not be toxic or irritating to the mucosa. A large proportion of monomer materials, which are inherently reactive materials with a relatively low molecular weight, possess a recognized or suspected adverse health effect. For this reason, it is an essential feature of the present invention that one does not use a monomer binder but an oligomer prepolymer having a molecular weight of at least 200, preferably at least 300, especially preferably at least 400, e.g. in the range 700 - 5,000 especially 1,000 - 3,000. The curing of such prepolymers is usually both faster and easier to control than curing 5 by polymerization from monomers.

The use of prepolymers also avoids a tendency for the coating to become sticky, which can occur when using monomers, especially when combining several different monomers.

Furthermore, when using a monomeric binder, the coating will shrink sharply during polymerization, which gives a physical bonding effect. However, such a shrunken coating may loosen upon immersion in water due to poor chemical contact with the substrate. If an oligomeric prepolymer is used instead, the shrinkage effect is less pronounced. In addition, the chemical contact or bond to the substrate is more efficient, the prepolymer being able to penetrate only a small amount of 15 into the substrate to establish a suitable bonding effect, whereas the monomer often penetrates deep into the substrate by diffusion and / or dissolution of the substrate, thereby the monomer is lost to the polymerization process and thus no longer helps the desired chemical bond.

In practice, it has been found that coatings made by the method of the invention are retained on the substrate and remain smooth even after dipping in water for 24 hours. These properties are also maintained during prolonged immersion in water. Thus, in a long-term experiment with immersion of a coated article made according to Example 1, the coating has proved to be durable even after several days of immersion. This is a very important property for catheters, which ensures a good effect both on insertion of the catheter and on removal after prolonged placement in the body. Even the tip of the catheter, which is particularly exposed during insertion and execution, will retain its smooth surface.

DK 172850 B1 12

An advantageous type of radiation curable urethane acrylate prepolymers are radiation cure free radical polymerizable urethane acrylate prepolymers such as electron beam cure, laser beam cure or UV cure prepolymers.

Using UV-curing or laser-curing prepolymers, the presence of a photoinitiator is usually required, a compound which, by irradiation with ultraviolet light or laser beams, forms free radicals, respectively. Such photoinitiators are well known and any photoinitiator with these properties can be used in principle. However, since free radicals can be harmful to health, it is usually important to avoid residuals of such radicals in the finished coating. This can be ensured by using a photoinitiator which, in addition to the portion of the molecule active in the formation of the free radicals, contains an ethylenic unsaturation such that the free radicals during the polymerization process are copolymerized with the prepolymer. In this way, the presence of unfortunate, low molecular weight reactive compounds in the coating can be effectively avoided.

The technical developments in radiation-curing binders provide expectations of useful alternative embodiments of the invention, where instead of UV cure or laser beam cure, electron radiation is used. By these methods it is expected that the use of photoinitiator can be completely avoided.

A further important feature of the binder (a) used is that it must have a sufficient affinity for the material from which the article to be coated is made.

One of ordinary skill in the art will be able to easily determine the affinity of a selected binder on the basis of the solubility parameters of the material and the binder, respectively, or by simple immersion tests to examine whether the binder attacks the material and binds to it.

DK 172850 B1 13

The radiation curable urethane acrylate prepolymers used according to the invention as component (a) are distinguished by themselves having a certain hydrophilicity combined with a good affinity for e.g. PVC, and are especially suitable for flexible substrates.

As the hydrophilic polymer (s) to ensure the sliding effect, i.e. the low friction of the coating when moistened, polyvinylpyrrolidone, polyethylene glycol, CMC and alginate can be used.

A prerequisite for a polymer to produce a friction-reducing effect and thus to function as a sliding polymer is related to the hydrophilic properties of the polymer. Thus, a sliding action can be obtained with a water-soluble polymer which can be released slowly in the form of a viscous lubricating solution. However, the sliding effect can also be achieved with a hydrophilic polymer which is only water-soluble to a limited extent, but which, upon contact with water, swells up, such a swollen aqueous polymer also gives a smooth surface.

As mentioned above, the urethane acrylate prepolymers used as the binder 15 (a) can provide an albeit limited hydrophilicity, which can be ascertained by a degree of swelling and water bonding after prolonged contact with water. This provides a limited, albeit limited, reduction in friction and may provide an advantage if the actual hyrophilic slip polymer has been too strongly leached from an object which has been inserted into a body cavity for a long time.

Although, in certain cases, the binder (a) may thus have a certain degree of hydrophilicity, however, in the present description and in the claims, the terms binder (a) and hydrophilic polymer (b), respectively, will be used in such a way as to distinguish between these two types in such a way that a binder (a) with a certain degree of hydrophilicity is not to be classified under the general term hydrophilic polymer (b).

DK 172850 B1 14

The content of the hydrophilic polymer (b) is at least 0.5, more preferably at least 6, especially at least 15 and more preferably at least 25 parts by weight per minute. 1 part by weight of binder (a). For coating materials for application to flexible articles, such as PVC or polyurethane articles, the content of the hydrophilic polymer (b) is preferably at most 40, more preferably at most 35, and most preferably at most 31 parts by weight. 1 part by weight of the binder (a).

For application to solid objects, e.g. metal or glass articles, the content of the hydrophilic polymer (b) is at most 60, more preferably at most 55 parts by weight per minute. part by weight of the binder (a).

Thus, as the hydrophilic polymer (b), 10 polyvinylpyrrolidone (PVP), polyethylene glycol or a combination thereof is usually used but not exclusively. You can also use CMC and alginate.

Useful hydrophilic polymers (b) will often have a molecular weight in the range of 10,000 to 500,000, e.g. between 20,000 and 400,000. As will be seen below, it is often advantageous to use a combination of a low molecular weight hydrophilic polymer, e.g.

15 having a molecular weight of between 10,000 and 60,000, and a high molecular weight hydrophilic polymer, e.g. one having a molecular weight of between 100,000 and 500,000, such as between 300,000 and 400,000.

The desired sliding effect is presumably achieved especially by a slow release of the slide depolymer. In order to achieve the desired effect, it has been found that the molecular size of the hydrophilic polymer is critical to the effect obtained, leaching molecules with a smaller molecular size faster than high molecular weight polymers. Conversely, high molecular weight polymers give no immediate slip effect, whereas low molecular weight polymers give immediate slip effect. Therefore, to obtain the desired sliding effect, a combination of gide polymers of different 25 molecular sizes can be advantageously used, which, when using PVP as a sliding polymer, can be exemplified by a combination of PVP K30 (molecular weight about 40,000) and PVPK90 (molecular weight about 360,000). PVP K30 and K90 are supplied as standard products by several DK 172850 B1 15 suppliers, e.g. BASF, Germany, and GAF CHEMICALS CORPORATION, Wayne, New Jersey, USA.

On the basis of the experiments performed so far, a mixing ratio between PVP K30 and PVP K90 has approx. 1: 1, e.g. between 1: 2 and 2: 1, proved particularly useful. Using PVP with other molecular weights or using other hydrophilic polymers, those skilled in the art will readily find suitable combinations of hydrophilic polymers to achieve a similar effect.

It is possible to use a particular type of hydrophilic polymer as part of the hydrophilic polymers used, namely a hydrophilic polymer of type b1 which is only partially or limited soluble in the dispersant phase. This property is seen e.g. in polyethylene glycol (PEG), which is water-soluble but which, like proteins, precipitates in a concentrated saline solution. Thus, by using such limited soluble hydrophilic polymers, this polymer or a portion thereof can enter the disperse phase of the coating material. In this way, a portion of the hydrophilic polymer component can be intimately mixed with the binder. This ensures an excellent affinity between the binder phase and the hydrophilic phase in the coating, ie. the phase remaining of the dispersant after drying the coating.

The hydrophilic polymer (b) may, as mentioned, be constituted by a combination of one or more hydrophilic polymers which are only soluble in the dispersant phase, herein designated type b1, and one or more hydrophilic polymers which are substantially completely soluble in the dispersant phase. , herein referred to as type b2. However, the hydrophilic polymer (b) may also consist of only one of these two types, in particular type b2 alone, since type b1 can often only be used only under certain special conditions, i. depending on how limited the solubility is. In practice, it has been found that practically all 25 weight ratios between b1 and b2 are applicable. Thus, e.g. 0.5 to 8 parts by weight of bl are used. weight portion b2, such as 1.0 to 3.0. Experiments have also been carried out with 29 parts by weight of bl. part by weight b2.

DK 172850 B1 16

In working with the prior art hydrophilic coating materials for articles intended for insertion into voids in the human body, it has been found that it is often desirable to incorporate an osmolality enhancing compound, e.g. sodium chloride, in the coating to avoid dewatering of the coating when in contact with body fluids. To solve this problem, it is proposed according to European Patent Specification No. 217,771 that after application and curing of the hydrophilic coating in a further step, the article is treated with a solution of an osmolality increasing compound, e.g. a saline solution. In the process of the invention, such an additional treatment step is avoided, since the osmolality-increasing compound 10 may be present in the coating material as a component of the dispersant phase.

As mentioned above, the coating material usually also includes an osmolality enhancing compound, usually in the form of sodium chloride. On the basis of tests performed, it is believed that this component can have a significant influence on the structure of the coating material at least in the embodiment in which a partially soluble hydrophilic polymer of the type (b1), such as e.g. PEG besides soluble hydrophilic polymers of type (b2) e.g. PVP. Namely, these experiments show that PEG is not soluble in a 25% sodium chloride solution, whereas PVP is soluble in such 25% sodium chloride solution. Thus, it can be presumed that the presence of the osmolality-increasing compound (c) is instrumental in securing the particularly advantageous structure described above.

In order to obtain the above-described net-like structure in the finished coating, the most important requirement for the solvent (d) used is that the binder (a) used be insoluble therein, i.e. thus ensuring that the coating material will form a dispersion. In addition, it is important that at least a portion of the hydrophilic polymer (s) be soluble in the solvent (d).

For the sake of affordability and non-toxicity, in most cases it is preferable to use water as the solvent (d), since water meets the above conditions. Other DK 172850 B1 17 solvents which meet the mentioned conditions, such as lower alcohols, e.g. ethanol and 2-propanol, and esters, e.g. ethyl acetate, however, may also come into play usually in admixture with water.

The amount of the solvent (d) should usually be kept as low as possible, thereby ensuring that the coating material has a suitably high viscosity. This is important in order to be able to apply the coating with an appropriate layer thickness, preferably in a single application step. If an excessive amount of the solvent is used, it may become difficult to have the coating adhere to the article, as the coating material may then tend to bead off. In addition, a greater amount of 10 of the solvent will require more time and / or energy for the evaporation.

However, if the coating material tends to bead off, which occurs when the liquid coating material has too high surface tension relative to the substrate, the problem can be remedied in a conventional manner by the addition of a surfactant.

In some application methods, e.g. when spraying, it will often be necessary to use a larger proportion of the solvent, a lower viscosity being desired here.

An example of a coating material in which the amount of the solvent (d) is kept low may have one of the following compositions: 3.5 - 15 parts by weight of radiation curable urethane acrylate prepolymer (a), 100 - 450 parts by weight of hydrophilic polymer (b), 20 - 90 parts by weight of osmolality increasing compound (c), and 140 - 560 parts by weight of solvent (d), or 3.5 - 15 parts by weight of radiation curable urethane acrylate prepolymer (a), 0 - 140 parts by weight of the first hydrophilic polymer (b1), 50 - 450 parts by weight of the second hydrophilic polymer ( b2), DK 172850 B1 18 0-90 parts by weight of osmolality increasing compound (c), and 140-560 parts by weight of solvent (d).

The coating can be applied in a single step in any conventional manner.

However, the coating can also be applied on several occasions, especially if the coating material has a low viscosity.

The coating material according to the invention may contain, in addition to the specified ingredients, conventional auxiliaries and additives for coating materials. However, it has surprisingly been found that the coating material can be prepared to obtain a dispersion by a simple mixing of the components at a suitable temperature, e.g. heating to at least 60 ° C, without the use of a dispersing aid, e.g. an emulsifier. This provides a particular advantage, as conventional emulsifiers, usually required for the preparation of dispersions, can be irritating.

By applying the coating materials of the invention to articles which should be in contact with the human body, it is of great importance to avoid low molecular weight components, except for physiologically compatible ingredients such as water and non-toxic osmolality enhancers. compounds such as e.g. sodium chloride.

The optionally present osmolality enhancing compound may be any compound which provides an appropriate equalization of the osmotic pressure difference between the wetted coating and the surrounding body fluids. Such compounds are low molecular weight water soluble compounds, preferably those dissociated in aqueous solution. Examples thereof are particularly inorganic salts such as sodium chloride, potassium chloride, potassium iodide, potassium nitrate and calcium chloride or organic salts such as sodium citrate. In principle, other water-soluble compounds can also be used. Thus, sodium benzoate, mono- or disaccharides such as e.g.

DK 172850 B1 19 glucose and sugar alcohols such as sorbitol, which osmolality enhancing compounds are all mentioned in EP Patent No. 217,771 and the corresponding US patent no.

4906237.

In practice, it has been found that the coated article produced by the process according to the invention can withstand sterilization without becoming sticky. This sterilization takes place after packaging the article by treatment with water vapor and ethylene oxide at 60 ° C for a longer period, e.g. overnight. This is surprising, as one skilled in the art would expect that the coating, which after curing still contains a certain amount of water bound in the hydrophilic polymer, would become strongly adhesive under such conditions.

The binder used should preferably be a liquid binder so that the dispersion will be in the form of an emulsion. This ensures an advantageous confluence of the binder prior to curing. The best results are obtained with a relatively viscous binder.

The hydrophilic polymer (s) used should be a combination of a low molecular weight hydrophilic polymer and a high molecular weight hydrophilic polymer, e.g. because the use of a high molecular weight hydrophilic polymer alone may have difficulty obtaining a sufficiently thick coating, and such a high molecular weight hydrophilic polymer tends to become sticky if the amount of solvent is too low. These problems are solved by the fact that a low molecular weight hydrophilic polymer, in addition to its action as a sliding polymer 20, can also act as a kind of filler.

The process according to the invention appears to be a very environmentally friendly solution to the stated task, avoiding the use of hazardous solvents and monomers. This avoids problems with the disposal of harmful waste, as well as avoids the health risk and odor nuisances during manufacture as well as harmful 25 residues in the finished product.

Example 1 DK 172850 B1

A coating mixture is prepared from the following ingredients:

Ebecryl 4830 7.5 g

Uvecryl P36 0.15 g Polyethylene Glycol 35,000 120.0 g PVPK30 45.0 g PVPK90 52.5 g

NaCl 45.0 g

Water 280.0 g 10 Ebecryl 4830 is an acrylic urethane resin having a molecular weight of approx. 1200, supplied as 90% polymer solids in tetraethylene glycol diacrylate. Supplied by Radeure Specialties s.a., B-1620 Drogenbos, Belgium.

Uvecryl P36 is a copolymerizable photoinitiator in the form of unsaturated copolymerizable benzophenone. Supplied by Radeure Specialties s.a.

PVP K30 is a polyvinylpyrrolidone having a molecular weight of approx. 40,000 and PVP K90 is polyvinylpyrrolidone having a molecular weight of approx. 360,000.

From the above ingredients, the coating material is prepared by heating to 90 ° C using a magnetic stirrer. However, Ebecryl 4830 and Uvecryl P36 are first mixed before mixing with the other ingredients.

A PVC hose of a quality used in the manufacture of catheters is coated with the mixture, after which the coating is dried and cured by ultraviolet light.

DK 172850 B1 21

A dry, sterilizable coating is obtained which, when wetted, becomes very smooth and adheres well to the PVC hose used.

The weight ratio of hydrophilic polymers to the hydrophobic binder in the coating prepared is 29: 1.

5 The cured coating friction in the wet state is determined by a modification of the method of ASTM Dl894-90 using the test arrangement of FIG. 1, c of said standard. The test is carried out with a test block, which has two renderings on the underside. Two tubes made according to Example 1. are placed in these rows. The test block ensures a vertical load of 5,970 N. The friction measurement is carried out with wet 10 wash skin and the test drawing is carried out in such a pulling direction that the sample block slides like a carriage with the hoses as a medium. The test is carried out at a speed of 100 mm / min. and the sample length is 25 mm. In this test, with different tubes all coated by the method of Example 1, a kinetic friction factor of, respectively, is obtained: 0.172; 0.206; 0.198 and 0.171, without sterilization. Corresponding sterilized tubes were measured at 0.169, respectively; 0.197 and 0.15.

Example 2 This example illustrates the preparation of a coating material without sodium chloride content.

A coating mixture was prepared from the following ingredients: 20 Ebecryl 4830 7.5 g

Uvecryl P36 0.15 g

Polyethylene glycol 35,000 120 g PVP 16 g

Water 152 g DK 172850 B1 22

The ingredients were mixed together while heating to ca. 90 ° C using a magnetic stirrer.

In this case, the weight ratio of binder to hydrophilic polymer was 1:18.

The coating material was applied to a plastic and metal article, respectively, and the coating obtained in both cases showed satisfactory bonding and sliding effect.

Example 3 This example illustrates the preparation of a coating material comprising exclusively hydrophilic polymer of type b2.

A coating mixture was prepared from the following ingredients: 10 Ebecryl 4830 7.5 g

UvecrylP36 0.15 g PVP 30 45 g PVP90 52.5 g

Sodium chloride 21 g 15 Water 209 g

The ingredients were mixed together at heating to 90 ° C using a magnetic stirrer.

The weight ratio of binder to hydrophilic polymer in this case was 1:13.

The obtained coating material was applied to both a plastic and a metal article. In both cases, good adhesion to the article was obtained, a satisfactory hardening and a satisfactory sliding effect.

DK 172850 B1

Example 4 23 In a similar manner to the previous examples, a satisfactory coating material comprising hydrophilic polymers of both type b and b2 was prepared from the following ingredients: Ebecryl 4830 7.5 g

Uvecryl P36 0.15 g

Polyethylene glycol 35,000 217.5 g PVP90 7.5 g

Sodium chloride 45 g 10 Water 135 g The weight ratio of binder to hydrophilic polymer in this case was 1:30.

Example 5 The present example illustrates the preparation of a coating material exclusively comprising hydrophilic polymers of type b2: Ebecryl 4830 7.5 g

Uvecryl P36 0.15 g PVP30 100.4 g PVP90 117.1 g

Sodium chloride 45 g 20 Water 460 g

The ingredients were mixed together with heating to 90 ° C using a magnetic stirrer.

In this case, the weight ratio of binder to hydrophilic polymer was 1:29.

The coating material was applied to a PVC hose, after which the coating was dried and cured by ultraviolet light.

The resulting coating adhered well to the PVC hose and showed an excellent sliding effect.

Example 6 The present example illustrates the preparation of a coating material with a high proportion of hydrophilic polymer, which coating material is suitable for coating on metal and glass surfaces.

A coating mixture was prepared from the following ingredients:

Ebecryl 4830 7.5 g

Uvecryl P36 0.15 g

Polyethylene glycol 35,000 227.7 g PVP 30 82.9 g PVP90 101.9 g

Sodium chloride 84 g

Water 529 g The weight ratio of binder to hydrophilic polymer in this case was 1:55.

The coating material was applied to a glass and metal surface, respectively.

After drying the coating and curing by UV light, a very satisfactory coating was obtained which adhered well to both the glass and metal surface.

in

Example 7 DK 172850 B1 25

A mixture having a ratio of hydrophobic binder polymer to hydrophilic polymer of 1: 1.0 was prepared with the composition shown in Table I below. This coating material was applied to a plasticized PVC catheter and cured by UV-5 irradiation as described in the previous examples. The coated catheter was then immersed in water for 10 seconds. Significant friction reduction was obtained compared to the uncoated catheter. A rapid release of water-soluble friction-reducing polymer was observed, which was readily ascertained by gently rubbing the moistened catheter with two fingers. This release of hydrophilic polymer could also be easily confirmed by subsequently rubbing the fingers together. The adhesion to the catheter was excellent.

Example 8

A mixture with a hydrophobic polymer to hydrophilic polymer ratio of 1: 0.5 was prepared with the composition shown in Table I. By curing and testing 15 as described in the previous example, it was determined that release of hydrophilic polymer and a friction reducing effect could also be observed in this case.

Example 9

A mixture having a ratio of hydrophobic polymer to hydrophilic polymer of 1: 0.1 was prepared with the composition shown in Table I. The same curing and testing as described in the previous examples was carried out, but in this case no significant friction reduction or release of hydrophilic polymer could be detected.

Claims (8)

15 Patent claims. A method of making an article having a wetting friction-reducing coating comprising a binder (a), a hydrophilic polymer (b) and, if desired, an osmolality-increasing compound (c), characterized in that 20 a) a binder in the form of a radiation curable urethane acrylate prepolymer having a molecular weight of at least 200, (b) one or more hydrophilic polymers selected from polyvinylpyrrolidone, polyethylene glycol, CMC and alginate, (c) if desired, an osmolality enhancing compound, and DK (D) a solvent or a mixture of solvents wherein (a) is substantially insoluble using 0.5-60 parts by weight of hydrophilic polymer (b) per liter. part by weight of binder (a), produces a dispersion, applies the dispersion to the article, removes the solvent or any of them. thereof, and cures the binder. Coating material comprising a binder (a), a hydrophilic polymer (b) and, if desired, an osmolality-increasing compound (c), characterized in that it is designed as a dispersion comprising a dispersion phase dispersed in a dispersion agent phase, said dispersion. is prepared from (a) a binder in the form of a radiation curable urethane acrylate prepolymer having a molecular weight of at least 200, (b) one or more hydrophilic polymers selected from polyvinylpyrrolidone, polyethylene glycol, CMC and alginate, (c) if desired, an osmolality enhancer and (d) a solvent or a mixture of solvents wherein (a) is substantially insoluble and contains 0.5 - 60 parts by weight of hydrophilic polymer (b) per liter. 1 part by weight of binder (a). Coating material according to claim 2, characterized in that the hydrophilic polymer component (b) is composed of (b1) one or more hydrophilic polymers which are only soluble in the dispersant phase and (b2) one or more hydrophilic polymers which are essentially completely soluble in the dispersant phase. 28 DK 172850 B1 Coating material according to claim 3, characterized in that it comprises 3.5 to 15 parts by weight of radiation curable urethane acrylate prepolymer (a), 60 to 240 parts by weight of the first hydrophilic polymer (b1), 50 to 200 parts by weight of the second hydrophilic polymer (b2). , 5 22 - 90 parts by weight of osmolality increasing compound (c), and 140 - 560 parts by weight of solvent (d). Coating material according to claim 3, characterized in that the hydrophilic polymer (b1) is polyethylene glycol (PEG), that the hydrophilic polymer (b2) is polyvinylpyrrolidone (PVP), and that the solvent (d) is water. Coating material according to claim 2, characterized in that the binder (a) is one or more radical-polymerizable binder. Coating material according to claim 2, characterized in that the binder (a) is a UV curable or laser beam curable binder and the coating material further contains a photoinitiator. Coating material according to claim 7, characterized in that the photoinitiator is an inherently free photoinitiator capable of forming free radicals, the photoinitiator having such a structure that each of the free radicals formed contains an ethylenic unsaturation. 20